著者

吉田 哲也 五十嵐 敏文 朝倉 國臣 宮前 博子 彌富 信義 橋本 晃一

出版者

一般社団法人 資源・素材学会

雑誌

資源と素材 (ISSN:09161740)

巻号頁・発行日

vol.120, no.10,11, pp.577-583, 2004 (Released:2006-05-09)

参考文献数

22

被引用文献数

1 3

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To reduce the volume of precipitates generated by the neutralization of acid mine drainage (AMD) containing high concentrations of Fe and As, ferritization of the precipitates was attempted by a two-step neutralization process in which magnesium oxide (MgO) was used as the first neutralizer and sodium hydroxide (NaOH) as the second. Batch neutralization experiments with MgO and continuous flow experiments by the two-step neutralization were conducted in laboratories and an AMD treatment plant. The results showed that the precipitates by the neutralization were magnetized in the continuous flow experiments, although there was Al and Si that prevented the generation of ferrite in the AMD. This indicates that ferrite was formed from the precipitates after removing most of the soluble Al and Si by the first neutralization. In addition, aging of the precipitates under reducing conditions and returning the aged precipitates to a ferrite tank were required to form ferrite. The molar ratio of As to Fe in the precipitates reached a constant value at pH>3.5. This suggests the coprecipitation of As and Fe.

著者

植田 武 松井 紀久男 島田 英樹

出版者

一般社団法人 資源・素材学会

雑誌

資源と素材 (ISSN:09161740)

巻号頁・発行日

vol.121, no.9, pp.438-445, 2005 (Released:2007-02-24)

参考文献数

9

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Increased opposition from environmental groups is severely restricting the operation and planning of large-scale surface mines in the world. Some projects of surface mining will have to be cancelled and downsized due to environmental issues. Under this social situation, the mining industry has started the campaign and the public relations for the importance of extracting and using coal resources in order to mitigate the protection. It has been recognized throughout the industry that planning is essential to minimize the effects of mining on the environment. Environmental management and rehabilitation are now integral parts of planning for mining.Mines have a finite life that ceases when the mineral has been fully extracted. During the life of mine, mining, especially surface mining, has the potential to have environmental effects that extend beyond the confines of the mine boundary. These include erosion with increases in sedimentation and turbidity in surrounding water courses and leaching of salts that also result in the reduction of water quality. These effects may range from minimal to quite severe and widespread, depending upon the physical and chemical properties of the overburden and reject materials, the climate and location of the mine, and its relationships with surrounding land uses. Rehabilitation of mines is aimed towards the projected future land-use of the area.This paper describes surface mining systems in Australia and then discusses the factors that should be considered in order to avoid potential environmental issues resulting from surface mining when developing a new surface mine.

著者

笹木 圭子 小林 弘幸 恒川 昌美

出版者

一般社団法人 資源・素材学会

雑誌

資源と素材 (ISSN:09161740)

巻号頁・発行日

vol.117, no.9, pp.747-752, 2001 (Released:2006-01-08)

参考文献数

10

被引用文献数

3 4

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Aragonite-type of light calcium carbonate was synthesized by the successive reaction using calcined-hydrous scallop shells and calcined lime stones in the aqueous system with Mg2+ ions under the CO2 bubbling. In order to obtain the high aspect ratios of aragonite, the reaction temperature and concentrations of Ca2+ ions in the 2nd step were important. The aspect ratio of aragonite increased when the reaction temperature was higher in the 2nd step than in the 1st step of the successive reaction. When the smaller amounts of calcium source were added in the 2nd step than in the 1st step, and the reaction temperature was lower in the 2nd step than in the 1st step, large particles of aragonite were produced with no smooth surfaces. The successive reaction was useful to extend the variety of morphologies in aragonite.